fix(resolution): remove catastrophic backtracking in the Vapor route regex

[pucedoteth]

Fixes #1544.

The bug

src/resolution/frameworks/swift.ts matched Vapor routes with:

/\b(\w+)\.(get|post|...)\s*\(\s*((?:[^,()]+,\s*)*)use:\s*([A-Za-z_][\w.]*)/g

[^,()]+ also matches whitespace, so each space after a comma can be consumed either by \s* on the current iteration or by [^,()]+ on the next one. When the call never reaches use: the match fails, and the engine explores every possible split.

Measured on app.get(arg0, arg1, … x) with no use: label:

arguments	ms
16	1.7
20	23.8
24	379.7
28	6100.1

~4× per additional argument. At 40 arguments it does not finish — I aborted a run after 10 minutes. Any generated Swift file with a long argument list on a .get/.post/… call stalls index/sync/MCP indefinitely.

The fix

Keep the repeated group to <run>, and match the gap before use: once, outside the loop:

((?:[^,()]+,)*)\s*use:

, is excluded from the class, so each iteration is forced to span exactly one comma-delimited run — there is only one way to split the input, and the failure is linear. 2000 arguments now match in 0.2 ms; the 40-argument case is 0.5 ms.

Behaviour is unchanged

The capture group is only ever consumed by segJoin, which pulls "quoted" literals out of it via /"([^"]*)"/g. Moving whitespace outside the group therefore cannot change a route path. I diffed old vs new across the real call shapes and the receiver/method/path/handler are identical on every one:

same  app.get("users", use: list)                          -> GET /users -> list
same  app.get(use: index)                                  -> GET / -> index
same  app.get("users", ":id", use: UserController.show)    -> GET /users/:id -> UserController.show
same  routes.post("a","b", use: h)                         -> POST /a/b -> h
same  app.get( "x" ,  "y" ,  use:  self.handler )          -> GET /x/y -> self.handler
same  app.get("users", BlogUser.parameter, use: show)      -> GET /users -> show
same  req.parameters.get("id")                             -> no match
same  Environment.get("X")                                 -> no match

The last two matter: use: is what discriminates a route from Environment.get(…) / req.parameters.get(…), and both still correctly fail to match.

Tests

Added does not backtrack exponentially on a call that never reaches use: (#1544) to __tests__/frameworks.test.ts — 40 arguments, no use:, asserts it completes under 1s and extracts no routes. It passes in 0.5 ms with the fix; with the old regex restored it does not terminate, so the assertion fails.

npm run build && npx vitest run is green: 2902 passed, 178 skipped, up from 2901 by exactly the new test.

Note for anyone reproducing locally: the suite needs npm run build first — 54 tests in 15 files fail without dist/ because the CLI tests spawn dist/bin/codegraph.js.

The three sibling regexes in this file ((?:\w+\s*,\s*)* in the SwiftUI/UIKit patterns) are not affected — \w and \s are disjoint, so there is no ambiguity to backtrack on. I left them alone.